Annealing furnace



R. G. L E TOURNEAU March 28, 1944.

ANNEALING FURNAC E Filed Deo. 28, 1942 2"Sheets-Sheet 2 INVENToR R. GLeYbur-neaw Patented Mar. 2S, 1944 ANNEALING FUnNacn Robert Gilmore Le Tourneau, Peor-ia, Ill., assignor to R. G. Le Tcurneau, Inc., Stockton, Calif a corporation of California Application December 28, 1942,Serial No. 427%,353

3 Claims.

This invention relates to annealing furnaces; it being the principal object of the invention to provide an annealing furnace which includes a oor assembly and a separate hood assembly, here illustrated of dome-shaped configuration, seated on the oor assembly and forming therewith an enclosed re chamber; the hood assembly being removable, by means such as a crane, to permit of placement of the work on, or removal thereof from, said floor assembly,

An additional object of this invention is to provide an annealing furnace as in the preceding paragraph in which said furnace includes a unique venting arrangement for the gases of combustion; such arrangement,includingV a cen.- tral iiue opening in the floor assembly, 'and a horizontal flue disposed beneath the floor and communicating with said opening.

It is also an object of this invention to provide an annealing furnace which includes, in combination with a floor assembly and a separate and removable hood assembly, novel sealing means between said assemblies when in engagement; said sealing means including an annular, downwardly projecting lip on the hood assembly seating in an upwardly opening trough on the floor assembly, said trough having a bed of granular nre-resistant material, such as sand, therein.

A further object of the invention is to produce a simple and inexpensive device, and yet one which will be exceedingly effective for the purpose for which it is designed.

These objects I accomplish by means of such structure and relative arrangement of parts as will fully ap-pear by a perusal of the following specification and claims.

In the drawings similar characters of reference indicate corresponding parts in the several Views:

Figure 1 is a sectional elevation of the improved annealing furnace.

Figure 2 is a sectional plan of reduced size, partly broken away, taken on line 2--2 of Fig. 1.

Referring now more particularly to the characters of reference on the drawings, the numeral I indicates a horizontal base ring of substantial diameter and formed of inwardly facing channel iron, said ring being seated on the ground 2.

The floor assembly of the furnace is mounted on top of the base ring and comprises a circular metallic floor plate 3 of slightly greater diameter than the base ring I, and seated concentrically thereon. Adjacent its periphery the circular oor plate 3 is tted with an upwardly opening annular trough 4; said trough being of channel annular form in section and having a sand bed V5 in the bottom thereof. Inwardly of the annularV trough Il the floor plate 3 is covered with a layer 6 of fire resistant vermiculite plaster; a floor 1 of fire brick being formed on top of said layer of plaster. Ring I and member l are heat 'resistant-steel, cast in segments.

A flue opening 8 extends centrally through the floor plate 3, layer 6 and re brick loonl.l 7A horizinal ue is disposed between the floor plate @i and ground 2, and extends from the flue opening, with which it communicates, `radially through the base ring I to connection laterally outwardly of the furnace with a stach "(noft shown).

The hood assembly, which cooperates with the above described floor asserribly,` comprises the following:

A dome-shaped outer shell It having a diameter at the bottom greater than the diameter of annular trough li, is normally disposed above and supported by the iioor assembly. An annular, horizontal shelf II, here shown as comprising two annular plates bolted together as at I2 in overlapping relation, is secured to the lower end of the dome-shaped shell I0 and extends radially inwardly therefrom in overhanging relation to the annular trough Il. An annular lip I3 is formed on and depends from the inner edge of shelf II, said lip seating on the sand bed 5 in said trough 4 whereby the dome assembly is supported concentrically by the floor assembly. The sand bed 5 forms a seal between the lip I3 and the trough i to prevent undesired escape of the gases of combustion from the enclosed fire chamber I4, which is formed by the floor and hood assemblies when in engagement.

The outer shell Iii is provided with an inner lining I5 of re resistant Vermiculite plaster; the shelf Il preventing displacement of said lining from the shell. The interior side wall of the dome-like hood assembly above described is lined with fire brick which lining extends vfrom the shelf Il vertically upward a distance approximately half the diameter of the dome. Burner ports Il, generally tangentially disposedI are formed in the dome-like hood assembly at circumferentially and symmetrically spaced points. Burners I8 project into said port-s, and fuel is fed to said burners by slack, nexible conduits (not shown).

Circumferentially spaced lifting loops I9 are fixed to the shell Il) exteriorally thereof; said loops being adapted for connection to a multiple lead hoist chain or cable (not shown), which is operative to lift the dome-like hood assembly vertically relative to and clear of the floor assembly, to permit of placement of Work on the floor 1, or removal of the work therefrom after an annealing operation.

In operation, when the dome-like hood assembly is seated in sealed relation on the floor assembly, work disposed on the fire brick iioor 1 is exposed directly to the heat from the burners I8; all gases of combustion passing downwardly through the fiue openings 8 and thence escaping from the furnace through the horizontal ue 9. This nue opening and flue arrangement in and below the bottom of the furnace assures maximum efficiency of the furnace and a minimum B. t. u. loss.

As the dome-like hood assembly is removable from the floor assembly, the work may be readily placed on or removed from the latter, even though the work may be bulky and weighty.

To support and reinforce the plaster I5 depending hooks 20 are welded on the shell I0 before the plaster is applied, Wire 2| extending between and supported by the hooks serving as a further support for the plaster.

From the foregoing description it will be readily seen that I have produced such a device as substantially fulfills the objects of the invention as set forth herein.

While this specification sets forth in detail the present and preferred'construction of the device, still in practice such deviations from such detail may be resorted to as do not form a departure from the spirit of the invention, as defined by the appended claims.

Having. thus described my invention what I claim as new and useful and desire to secure by Letters Patent is:

1. An annealing furnace comprising a metallic oor plate of circular configuration, means supporting said plate horizontally, a circular floor of nre resistant material formed on said plate in concentric relation thereto, the floor being of lesser diameter than the plate, an annular upwardly opening trough on the plate in surrounding relation to said oor, means securing the trough to said plate, an initially separate domelike hood assembly disposed symmetrically above and forming with said floor an enclosed fire chamber, and a depending annular lip on the.

hood seating in said annular trough in supporting relation to the hood, the trough having a bed of fire resistant material therein.

2. An annealing furnace comprising a metallic floor plate of circular configuration, a concentric base ring supporting the plate horizontally, a circular floor of fire resistant material formed on the plate in concentric relation, the plate being of greater diameter than the base ring and iioor and extending radially out beyond the peripheries thereof, an annular upwardly opening trough on the plate in surrounding relation to said iioor, securing bolts extending from the trough through the plate radially outwardly relative to said base ring, an initially separate dome-like hood assembly dispcsed symmetrically above and forming with said floor an enclosed lre chamber, and a depending annular lip on the hood seating in said annular trough in supporting relation to the hood, the trough having a bed of nre resistant material therein.

3. An annealing furnace as in claim 2 in which said trough is segmental whereby to facilitate removal and replacement thereof.

ROBERT GILMORE LE TOURNEAU. 

